The present invention relates to a brake control system for controlling an operation of a brake apparatus of a vehicle.
A brake apparatus of a vehicle can provide various controls by using, for example, a negative-pressure actuator, an electronic actuator, and a wheel pressure control mechanism. Examples of such controls include a boost control and a brake assist control for assisting a force that a driver exerts to operate a brake, an anti-lock control for preventing a wheel from being locked during a brake operation by adjusting a brake force for each wheel according to a road condition, a vehicle-running state or another factor, and a vehicle stability control for improving steering stability by preventing understeer and oversteer.
Japanese Patent Application Public Disclosure No. 2007-112426 discloses an electric booster detecting driver's operation amount of a brake pedal and controlling an operation of an electric actuator driving a primary piston based on a relative displacement between an input member coupled with the brake pedal and the primary piston of a master cylinder. This electric booster enables execution of various brake controls such as the boost control and the brake assist control.
There is known a regenerative cooperation brake control as one of those brake controls. In a so-called hybrid vehicle or electric vehicle equipped with an electric motor as a power unit, the regenerative cooperation control collects kinetic energy as electric power by driving a power generator (electric motor) through a rotation of a wheel, for example, when the vehicle is slowed down or braked. The regenerative cooperative brake control is a brake control for adjusting a brake force to be generated by a brake apparatus by subtracting a brake effect from the operation of the generator (electric motor) from a brake amount corresponding to driver's brake operation, resulting in generation of a brake force as desired in total.
During execution of such a regenerative cooperation brake control, the control method based on a relative displacement between an input member and a primary piston as disclosed in Japanese Patent Application Public Disclosure No. 2007-112426 has to perform the control by converting a brake effect from an operation of the generator into a relative displacement between the input member and the primary piston, leading to complicated calculations and a cumbersome control. As a result, it becomes difficult to provide a brake force according to driver's brake operation amount, and unable to offer excellent brake operation feeling. Further, in other controls, it may become difficult to appropriately perform the control based on a conversion into a relative displacement between the input member and the primary piston.
Therefore, an object of the present invention is to provide a brake control system capable of appropriately performing various controls.